


Copper

by 7PercentSolution



Series: Periodic Tales [7]
Category: Sherlock (TV)
Genre: Autistic Sherlock, Case Fic, Chemistry, Gen, Kidlock
Language: English
Status: Completed
Published: 2016-07-23
Updated: 2016-07-23
Packaged: 2018-07-26 06:39:06
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 14,605
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7564066
Author URL: https://archiveofourown.org/users/7PercentSolution/pseuds/7PercentSolution
Summary: <blockquote class="userstuff">
              <p>CU 29<br/>Copper is an orange-red malleable metal with a high electrical and thermal conductivity, the second highest among pure metals at room temperature. In use for over 10,000 years, more than 95% of all copper used by humanity has been mined and smelted since 1900. The cultural role of copper has been important, particularly in currency. Romans in the 6th through 3rd centuries BC used copper lumps as money, but roughly half of all copper mined is used to manufacture electrical wire and cable conductors.</p>
            </blockquote>





	1. Chapter 1

Mrs Walters came into the conservatory where Mycroft was reading. It was an overcast day in early July, with blustery showers, so he was trying to get a head start on his book list for next term. After the compulsory subjects in first year, he was now able to focus on just two of the three areas. He'd opted to continue with economics and politics, letting philosophy take a back seat. Next term, he'd be doing British Politics and Government Since 1900, Theory of Politics, and Macroeconomics. By dropping the Philosophy element, he could also squeeze in International Relations. So, he was now working through Raymond Aron's 700 page tome,  _Peace and War: A Theory of International Relations_.

"Mrs Walters, you're hovering."

The Scottish woman shifted a little uncomfortably, even though the young man had not looked up.

When she didn't answer, he did so, and took in the uncertainty in her stance.

"I'm sorry to interrupt your reading, but your brother…"

Mycroft sighed. "What is it this time, Mrs Walters."

"I'm not sure I can explain it; you'd better look for yourself to see whether it is as dangerous as it appears to be."

Without another word, he put his book down and followed her down into the kitchen.

Sherlock had colonised the big wooden table in the middle of the kitchen, and there was a clutter of glass beakers, a hot plate, various bottles with clear liquids, the kitchen scale and, most oddly, an old broken lamp. The flex that led to the plug no longer had its plastic insulation and bare twisted wires had been cut into several lengths about an inch long. Some pieces were sitting in Mrs Walters' kitchen scales. There was a faint chemical whiff in the air.

"Sherlock, what are you doing?"

"Experiment."

"I can see that. The question was, obviously,  _what_  experiment?"

"Metathesis, decomposition, displacement and oxidation-reduction reactions of copper."

Although to most people, those words would sound strange coming out of the mouth of a ten year old, Mycroft was never surprised by his younger brother's encyclopaedic knowledge.

Sherlock carried on, his enthusiasm making him rush his words. "It's  _brilliant_. The copper is dissolved, then precipitated through various compound forms, and eventually becomes metal again- from pure copper to copper nitrate, copper hydroxide, copper oxide, and then copper sulphate before it becomes pure copper again. If I do it right, then the same weight of copper will be recovered at the end of the five reactions."

Mycroft's brow furrowed. "That sounds rather complicated. Where did you learn about this experiment?"

"I read about it in one of Father's books in the library. It's really very interesting, and I'm learning how the chemical formula changes, too. See?" He gestured to the detailed pencil drawings of the chemical formulae on a pad by the sink, for each of the chemical reactions. "Want to watch?"

Without waiting for their agreement, he switched the hotplate on, measured 10 ml from the beaker of clear liquid and put it into the beaker with the copper wire.

A horrible smell started to bubble up out of the liquid, along with a brown noxious looking vapour. The ten year old seemed utterly unfazed by the process going on in the beaker. He said over his shoulder, "You might want to turn on the extractor fan."

"Sherlock, is that an acid?"

"Yes- nitric acid."

"Where did you get it?" This was said with an edge of concern that Mycroft decided not to hide.

Sherlock looked up at his brother. "I made it yesterday. I got the gardener to let me have some of his ammonium nitrate fertiliser, and then I concentrated some of stuff he uses to clean the concrete in the stable yard, into hydrochloric acid ….. Why?"

Mrs Walters looked distressed. "Is it safe?"

The smell quickly dissipated, but an evil-looking brown vapour cloud seemed to hover over the surface of the now very blue liquid in the beaker. Sherlock switched off the hotplate and looked carefully at the beaker. "Have you got any ice, Mrs Walters? It will help cool it down faster so I can get on with the next bit."

Mycroft crossed his arms in front of his chest. He remembered his school days in the lab at Eton- and all the safety equipment that they had to use, from goggles and gloves, to fume hoods and hazardous waste disposal bins, not to mention the expert supervision from the chemistry master.

"Stop right there, Sherlock."

The tone of his voice made Sherlock look up at him in annoyance. "What now? The next part is a tricky bit. If I had a decent chemistry set, I'd have a magnetic stirring bar, but as it is I have to use a glass stirrer and keep it going like mad while I put the hydrochloric acid in drop by drop until the litmus paper turns blue- then I will have copper hydroxide."

"There won't be a 'next part', Sherlock, it's too dangerous to do here in the kitchen without the proper safety equipment- and you need someone who knows what they are doing to supervise you."

He watched his brother's face. First disbelief, then anger. Mycroft did not move or show any sign of being moved. When his brother broke eye contact, he was half way to a full blooded strop; Mycroft recognised the signs.

"Mummy used to let me do things with my chemistry kit. Why are  _you_  being horrible?"

Mycroft sighed again. "Sherlock, when you did this sort of experiment last year, it was quite basic- I remember you using vinegar to take tarnish off pennies. But, this…strong acids, magnetic stirrers- chemical reactions that take precise measurements- you've outgrown the kiddie kit. You'll need proper equipment and someone who can teach you how to be careful."

"That's not fair! It's not my fault that I can do more now. I don't want to  _play_  at this, or do boring stuff; it's too important"

"Sherlock…"

His brother just cut him off, shouting, "I'm not like you; I can't just sit in a corner and read all day. That's what they wanted me to do- keep quiet, stay out of trouble, I'm fed up with not being allowed to do anything- that's what they said, and you're just like them!" Before Mycroft could say anything, Sherlock stormed out the back door of the kitchen.

Mycroft's heart sank. He turned back to the table. "I'll clear up this …mess, Mrs Walters."

"Och, don't trouble yourself. I'll manage. And, I will be careful with the acids- get the gardener up to dispose of them safely." She looked down at the table. "I'm just sorry that he's so upset. He's right, you know, it doesn't seem fair after all the time he spent on his own at that clinic."

"I know, Mrs Walters; he's so  _angry_  about it, and I don't blame him for that, but it's hard to know what's best."

On his way back to the conservatory, he decided that he would contact Dr Cohen and see what advice she might have to offer. Sherlock's temper was as volatile as the chemicals he wanted to work with.  _Time to get a professional's opinion._ Things were not going to go "back to normal", even with the best will in the world. He picked up his book-  _Peace and War_  seemed an apt description of his relationship with his brother at the moment.

oOo

The British Transport Police Officer was pacing to measure the distance between the electrified rail and the very dead body. The London Underground Manager was pacing too, but for a different reason. Although there was no tube station at Clapham Junction, both the Northern and District Lines tracks ran through the same area, and their trains had been stopped as well.

In the cold frosty morning, a Network Rail manager stood watching dispassionately, while DI Lestrade kept his eye on the two civilians standing on the platform about forty meters away. They were being held there by another British Transport Officer. Six of the seven men on the scene were wearing high visibility jackets, but one on the platform had refused.

"I know it's unusual, Mr Harker, but this civilian  _is_  different and will help us get to the bottom of the problem. So, just bend the rules and let us get on with the investigation, please."

The Met had been called in when the third body in as many months had turned up on the tracks about near Clapham Junction. As the UK rail network's busiest junction, anything that stopped trains coming from Brighton to Victoria and to and from Waterloo and the West Country had to be dealt with urgently. The previous two deaths- both rail maintenance inspectors- had been put down as an unfortunate co-incidence of accidental deaths. The first man was electrocuted by coming into contact with the live rail of the London Underground tracks. The second one appeared to have been hit by a train, whilst inexplicably walking the track late at night back from the depot.

But, when this third inspector was also hit by a train, suspicions flared and the Met was called in.

Now faced with the fact that thousands of angry commuters were being re-routed through other stations until the Murder Investigation Unit could process the scene of crime, the Network Rail Manager was cold, needed a cup of coffee and, more important, his superior off his back about yet another delay to trains. It would be just his luck if his boss was actually on one of those trains stuck somewhere on a branch line in Putney. Harker decided that Health and Safety regulations could get stuffed.

He nodded, and Lestrade beckoned John and Sherlock onto the tracks.

Sherlock stalked over to the body; he didn't like being kept waiting, so made no effort to be civil to the Transport Officers or the Network Rail manager. He crouched down beside the body on one side, whilst John knelt on the other. The brunet examined the body, focusing on the hands and then searching the pockets.

"Lestrade, get someone to stand exactly where the other two bodies were found."

No please was added to leaven the abrupt command.  _God, his social skills need work; must have a word with John about that._  Lestrade was used to it, but when people other than his own team were on a crime scene, such behaviour undermined his authority too much.

He grimaced and then said apologetically, "Sorry, lads, would you mind?" The two Transport officers grudgingly took up their positions, the first some fifty meters down the southbound fast line, the other tangentially across, almost a hundred yards away on the tracks that led to the depot for the trains that terminated at Clapham.

Sherlock stood up and watched them take their positions, then looked down at his phone screen. From where Lestrade was standing, he had no idea what Sherlock was looking at.

The Network Rail man looked equally suspicious. "What's he doing?" The two men watched as Sherlock turned slowly, making a complete 360 degree circle whilst scanning the horizon. He looked down at the phone again and then nodded as if to himself. John stood up and the two men came back to the others.

"You can move the body now, Lestrade, no need for forensics to process the scene. They won't find anything, and the case has been solved anyway." The brunet turned to the manager. "Once the body's moved you can put the power back on, although I suspect that you will find the signaling to let the trains out of the depot will not be working when you do."

Not one of the British Transport officers, the London Underground man or the Network Rail manager made a move.

Sherlock rolled his eyes and sighed. "Very well, let's just annoy every commuter in south London for a little while longer, shall we?"

Lestrade kept his temper. "Just get to it, will you, Sherlock?"

"Right- in the pocket of the dead man, I found this." He held out a metal object, about six inches in length.

Harker scowled. "That's a key component of a signaling device. Oh shit! That means he was trying to steal it when he got hit."

Sherlock rolled his eyes. "No, that is what you are  _meant_  to think! There were no grease marks or dirt on his hands, which he would have if he had stolen this. So, no, this was planted in his pocket. This is the aftermath of cable theft gone bad, but not in the way you're thinking. The two previous bodies were found on the same trajectory – leading to that small building over there beside the train shed. Do tell us what's in there, Mr Harker."

The Network Rail manager looked over at the small building. "That's the supply store for the maintenance work we've been doing, part of the Clapham to Waterloo upgrade."

"And now tell us what will be on large wooden wheels in that shed?"

Harker looked startled. "Oh! Copper cable!"

Sherlock snorted. "At last, the penny drops. Yes, Mr Harker, you will find 100 percent pure copper strands that have an amazing value to recyclers who are more than happy to look the other way when organised crime brings them a regular supply of high grade metal."

The manager bristled. "We know that, of course we do. Cable theft costs the rail industry £16 million a year, and every time some tom, dick or harry comes along to nick one of the copper elements of the signal mechanism, it means that hours of commuter delay cost even more. With the price of copper soaring on world commodity markets, thefts from tracks have gone up fourfold in the past two years. But, that's why that store shed is protected by really secure locks and CCTV cameras."

Sherlock just shook his head. "Put yourself in the shoes of the criminal and choose- instead of trying to nick a short length of cable and bits from the tracks where stealing risks life and limb, why not go for it in mass quantity in a nice convenient shed? If you investigate, you won't find any prints or signs that the lock has been forced. Why? Because for them, this is the egg laid by the Copper Goose- an unending supply of copper in conveniently available form. Somebody who is authorised to use that shed is doing just that-oh and while he does his proper job, he also manages to steal the stuff. He's probably also cooked the books so cable going missing doesn't even show up. This is what organised crime does."

He looked down at the body. "This poor fellow probably saw something he shouldn't have, like the others, and paid the price. Easier to hide a body here in plain sight than almost anywhere else- all three had a legitimate reason to be on the tracks, all three could be first dismissed as accidental death if the bodies got hit by a train. And if you did get suspicious, just plant a bit like that in a pocket, and you all draw the wrong conclusion. Works every time, I am afraid." He gave the Network Rail manager one of his fake smiles.

The consulting detective now looked at the British Transport Police Officer. "Ignore the CCTV camera evidence; it's easy to subvert with a loop. Just put a new camera inside the shed, discretely, and I can guarantee that you'll find your thief. Better still, don't stop at the little guy who actually walks in, put a tracer on the cable and see where it shows up at a crooked recycling yard. They are supposed to be getting photo ID of anyone selling copper cable, and automatic number plate recognition might show you the cars being used to do it. Track it back to the top guys, and, who knows, you might net what the Staffordshire police did when they found £700,000 worth of copper in a single haul."

The consulting detective rubbed his gloved hands, his breath clouding in the frosty air. "Right, John, fancy a hot breakfast? I know a little café down Grant Street that serves a very good full English."

Harker looked at the Met DI as Sherlock walked off back up the line to the platform. "Who is that guy, Lestrade?"

Greg just smiled. "Just someone I know who has been rather helpful in the past. Now, can I suggest we follow his example, and get off the tracks so all those commuters can get into work?"


	2. Chapter 2

**Summary for the Chapter:**

> Copper, when exposed to air, often forms a green carbonate layer called verdigris. It does not react with water, but it slowly reacts with atmospheric oxygen forming first a layer of brown-black copper oxide (tarnish). Over time, this turns green as it combines with sulfur compounds in the air. This layer stops the further, bulk corrosion, giving the copper an impenetrable layer of protection.

"Can I get you some more soup, Doctor Cohen?" Mrs Walters dipped her ladle into the tureen, and when the dark haired young woman nodded, she put another portion of the mushroom soup into her bowl. When Mycroft nodded as well, she served him seconds, as well.

"This is a soup to die for, Mrs. Walters; really, you must give your cook my compliments. I haven't had home-made soup for …must be months."

The Scottish woman beamed. "Well, I'll thank you for the compliment, because Cook's on her annual holiday and I'm the one wielding the knife in the kitchen this week. It's just a simple supper tonight, I'm afraid, doctor, but tomorrow I'll do better. I am sure that you're too busy at the hospital to look after yourself properly, so let me spoil you for a while."

Esther Cohen smiled, but then looked thoughtful. "Actually, Mrs Walters, you must call me Esther. You, too, Mycroft. If Sherlock is ever going to accept me, then we've got to get him thinking of me as something other than yet another beastly doctor."

"Of course, my dear. I understand perfectly. I will pass that on to the rest of the staff. Now I'll be off to the kitchen to see what's happening to my fish."

Esther watched the kindly woman leave, and then smiled at Mycroft. In a whisper, "She's like something out of a film. In fact, this whole place is. When you invited me down, I had no idea that this is where you lived."

The psychiatrist had arrived only an hour ago, tired and hungry after her last thirty six hour hospital shift. She'd accepted his invitation readily. "Really, I had already booked the the next four days off to finish an article that I've been promising a journal for months. Once you telephoned, I actually had a reason to stop procrastinating, and finished it all but the references and a few tables. I can do that while I'm with you."

"Are you certain that you want to take on a private patient?" Mycroft was trying to be diplomatic. If the young doctor was too busy with her hospital work and research, then he needed to know now; if she was, then the visit would be needed to pick her brain about a suitable therapist. He had come to trust her judgement over the past three months.

She gave him a reassuring smile. "Normally, someone in my position wouldn't be seeking a private patient. I'm at least three years away from wanting to set up my own practice. But, I meant what I said when I spoke to you on the phone. If there is any way I can help, then I will. Sherlock is a special case. You've been through enough to get this far. So, if – and I do mean if- he is willing to engage, then, yes, I will do what I can."

She had grown to respect Mycroft. When he'd first sought her help at Oxford, she had been impressed with his mature attitude and manners. The time since must have been horrible for him. Still having to deal with his own grief over his mother's death, he had been determined enough to do what was needed to rescue Sherlock from the clinic, even if it had cost him his relationship with his father. To abandon him now would be too cruel. She just hoped that she'd be able to reach Sherlock. Based on what she had seen at the Mount Sinai centre, she wasn't sure.

The two of them agreed that if Sherlock was to accept her therapy, he would need to meet her on familiar territory, and in a way that did not awaken the distrust that he'd shown to anyone in a white coat. "I only saw him twice at my uncle's facility during the two weeks he was there. Unfortunately, I was on a beastly shift cycle then; new joiners tend to get the worst assignments. The first time, he ignored me completely, the second he was sound asleep. So, hopefully I have not made him too distrustful."

Over the light supper, the two of them talked. "You said on the phone that his mood has been volatile. Could you explain more?" She took the opportunity to return to her soup.

Mycroft put his spoon down for a moment, to butter his roll. "He wouldn't budge out of his room for the first three days. It took nearly a week before I could talk him into getting dressed. He spent two whole days in the Library, totally engrossed in Father's chemistry books. He then sort of. ..reclaimed the house. Spent time just wandering about, looking at things, picking up things. It's as if he'd forgotten them, and wanted to re-familiarise himself."

"That's normal. One of the side-effects of ECT is memory loss. So, a little uncertainty is to be expected. And when a child has been institutionalised for months, they can get fearful of being suddenly able to have all the freedom that comes with being at home." She took a bite from the warm bread roll.  _God's above; she even does her own baking._  It was heavenly. Ever since starting at the Royal Bethlem Hospital, she'd been living on a diet of frozen meals.

The young man across the table had impeccable manners. She watched as he filled his soup spoon again the old-fashioned way, by dipping it away from himself. It was a simple act, but one in keeping with the aristocratic background. What might look like an affectation in someone else just looked natural with him.

"Well, he soon took advantage of that freedom. Last week, he disappeared for six and half hours, and I finally found him at the far side of the estate, almost four miles from the house. On the one hand, I was glad to see that he felt confident enough to roam at will..."

Esther completed the sentence for him. "…and on the other, it must have been worrying that he was unsupervised for so long a time." She had a lot of sympathy for the young man, thrust into a parental role like this.  _So difficult; he's scarcely more than a child himself._

But the object of her scrutiny responded quietly, in an adult manner with polished poise. "That was not the problem that led me to contact you, Doctor." She frowned at his use of the title. "…Esther; no, it was when I had to stop him from a rather hazardous chemistry experiment that he was doing in the kitchen. Sherlock lost his temper, started shouting and came close to a melt-down. I haven't seen one of those for at least two years. Then he stopped talking to me, or to anyone, and retreated to bed. He could always sulk for Britain, but this is different. This isn't a sulk; I think it might be more serious, perhaps depression. It's been three days. He won't talk, won't eat, won't take his pills. It's like he's gone back to square one, where he was almost a month ago. And because he's not taking the medication you prescribed …well, I just didn't know what to do."

She looked thoughtful at his description. "You need to understand something about what happens to a child when they are in hospital for such an extended period. They form a sort of shell- an impervious layer. It's a bit like silver, brass or copper- you know, the longer it goes uncleaned, the dirtier and more tarnished? Well, being in bed all day, drugged, without stimulation or the comfort of friends and family- it's a bit like that. The longer they are in, the heavier the tarnish that has to be cleaned off. What you see of them in a hospital is only the faintest hint of the shine that should be there- and that only happens if the patient isn't scared. It's safer under that protective layer. What happened with Sherlock this week sounds like he's just decided to hide behind that protection again. Have you told him about me being here?"

"No, but he will know. My brother, even when he is shutting himself down like this, is amazingly perceptive. My mother told me that doctors never understand him. They assume he has a sub-normal intelligence, because he won't communicate. My father believes them. Mother knew better, and so do I. He's amazingly bright, just… not normal. I wish I knew what went on his head, how to reach him. As he's grown up, he's learned how to hide the anxiety. But I think it's still there. Mother found a way to keep him focused on things, and when he focuses, he is amazing. That experiment, for example, the one I stopped him from doing, was something out my father's first year university text book. With the right equipment and supervision, I have no doubt that he'd have done it perfectly."

He looked down at his empty bowl. As if she had seen his last spoonful, Mrs Walters arrived and whisked the bowls away to the side-board. She set warm plates in front of them. She returned with a silver dish, laden with freshly grilled Dover sole fillets. Esther used the silver fish servers she was handed to take one onto her plate. Once Mycroft had been served, the Scottish woman re-appeared at Esther's shoulder with a dish of new potatoes in parsley and butter. The aroma reminded her of how hungry she was.

Once the food had been served, Mycroft asked her if she would like a glass of wine.

"Only if you join me."

He nodded, and Mrs Walters brought a bottle of Pouilly-Fumé Baron de'L to the table, pouring them each a glass before returning it to the ice bucket. Esther spotted the vintage and was impressed.  _I could get used to this._

To stop the daydream, she returned to what they'd been discussing before Mrs Walters arrived. "What you've just described- a bright highly intelligent young boy -sounds more like an Aspergers, a high functioning autistic. It seems miles away from the locked-in Sherlock I saw at Mount Sinai. Being deprived of books, of stimulation for so long would have been very hard on him."

"I think that's what surprises me about the whole thing. The Sherlock I know would never have been content to just sit there. Until last summer, he still threw tantrums like a four year old. And his biggest complaint? He hated, absolutely abhorred being  _bored_. When I finished at Eton I spent most of last summer abroad with relatives, but the time I was here, I could see how much improvement there was. Instead of talking at me, we had the first real conversations ever. He was fascinated with chemistry and incredibly advanced. It was like no one had told him that nine year old couldn't do complicated formulas. But, by November I knew mother was dying. When I got home at Christmas, he knew something was dreadfully wrong, too. However horrible it has been for me, it's been far worse for him. Without her, I fear he has lost his way utterly."

"Well, don't despair, Mycroft. I hope to find a way to re-connect, starting tomorrow." She picked up her fish knife and fork and started in on the fish.

The next morning after breakfast, she went up with Mycroft to Sherlock's room. It wasn't where she expected. Unlike the other main bedrooms, Sherlock's was not off the main upstairs corridor. She had slept in an amazing room on that floor, with a four poster bed, and a pair of mullioned windows overlooking the garden. Instead, Mycroft led her down one of the wings and then up another flight of stairs. He explained as he went, "as children we both started in the nursery up in the east wing- a small bedroom, with an adjoining door into the nanny's room, and shared bathroom facilities. There's a playroom too, so we could be noisy children without disturbing the rest of the house. Sherlock just preferred it up there, and even when he was able to fend for himself and the nanny left, he refused to take the room that you slept in last night."

Mrs Wallace came out of a room carrying a tray- she shook her head, looking down at the untouched meal, before heading off down the stairs.

"Mycroft, I need to try to talk to him on my own. I don't mind you listening in from out here, but I'd rather you weren't in there. Might make him say what he thought you wanted him to say."

Mycroft laughed softly. "You don't know my brother, Esther. That's the last thing he would do." As she pushed open the door, he found himself wishing her luck. They all needed it, badly.

oOo

"Smashed, you say? Copper doesn't often 'break'- it bends, so what exactly did you find?"

Susan Chambers ran the Morse Fortescue gallery on the Kings Road. Her tale was piquing Sherlock's curiosity.

"Well, we specialise in small bronze pieces. Bronze is usually 88% copper and 12% tin, but this was special- pure copper, that had been treated to have that lovely green finish from the very start- makes it look old even when it isn't. The workmanship is superb. There were six in the set made by the Italian artist, Beppo Goldini. He used to work out of a studio in Hoxteth, but he's been gone for nearly nine monthes- said to have retreated to the hills of Calabria to do his next series. Very  _avant garde_ , very collectible, his pieces- incredible prices. They are abstract, but suggestive of animal forms. I've sold three, two more of the six are out on loan at corporate offices, and I've just got the one left in the shop. Or, rather, I did until I came in this morning and found it smashed. Flattened- looks like someone took a mallet to it and just bashed it flat until it looks like …a squashed piece of metal junk."

The Art Gallery owner was clearly distressed. "The Met's Art and Antiques Squad just called it vandalism- nothing was actually stolen, so they aren't interested. Didn't even send a detective, just a constable, who went through the motions, dusted for fingerprints and all, but said there was no evidence of a break-in, and asked if I thought any of the staff might have a grudge against the artist or me."

"And do they?"

She looked annoyed. "Of course not, Mr Holmes; I don't' know why someone would do it, but that's why I am here asking you to look into it. And it's not like this is the first time."

That raised a consulting detective's eyebrow. "Explain."

"Well, I contacted Beppo by e mail and told him about it; to be honest, I wanted to know if I could get a replacement. He replied that day before yesterday he'd been contacted by the Barnicot Bank offices to say that the two figures they had on display had been stolen. When the police investigated, they found the shattered pieces of the figures which were found in the courtyard of the bank the next morning. The bank called Beppo, wanting to know if he could fix them. He said, maybe in a couple of months' time, when he is back from Calabria."

"So, three statues in as many days. Does he have any idea who would want to do such a thing?"

"No. He is as perplexed as I am. I can claim on the shop insurance, and so can the Bank, but that's not the point. It's that fact that someone is going around smashing up beautiful pieces of art, and no one seems able to stop them. Will you help me find out who is doing this?"

Sherlock nodded. "Leave it with me. I will not be able to do anything today or tonight; I have a commitment to be at New Scotland Yard this afternoon on another matter, but can pick this up in the morning."

She looked relieved. "Thank you, Mr Holmes, for taking this seriously."

When John came down the next morning to fix himself a cup of tea, he saw Sherlock's phone buzzing on the kitchen table. He called down the hallway to his flatmate, who was in the bathroom- "Sherlock- looks like you've got a text from Lestrade."

Sherlock popped his head out of the bathroom door, and John could see that he was in his pyjamas and blue dressing gown, with half of his chin was still covered in shaving foam. He brandished a razor, "Just read it to me, will you- my hands are a little busy at the moment."

" **8.12am Come instantly, 131 Pitt St Kensington GL** "

In less than three minutes, Sherlock emerged freshly shaved, buttoning up his shirt. "Coming, John?"

"Yes, but I need coffee if I'm going to miss breakfast. While you finish getting dressed, I'll get two takeaway coffees from Speedies. Meet you outside. If you get there first, try to flag a cab, but please, this time,  _wait_  for me."

It was a sore point. The last time he'd done this, Sherlock had been so focused on the case that he hailed a taxi, jumped in and left John to come running out of the café with the coffees. It cost twice as much as it should have to get the two of them to the crime scene and left John in a seriously grumpy mood for half the day.

Luckily, there was no queue at the café, and he emerged carrying the two hot coffees just as the front door of 221b banged shut behind Sherlock. The taxi to a backwater of Kensington was spent in silence as they both enjoyed the caffeine and the spectator sport of watching a cabbie pit his knowledge against the volume of London rush hour traffic. Thirty five minutes later, the taxi pulled up at the police tape at the end of Pitt Street, a side road between Kensington Palace and Holland Park. Sherlock hopped out and lifted the tape, walking to the front of white fronted terraced house at Number 131. The door was answered by a constable, who gestured them into the hall. "Lestrade is in the drawing room with Horace Harker, who's pretty shaken."

Sherlock went into the light filled living room that looked out onto the back garden. An exceedingly unkempt and agitated elderly man, clad in a flannel dressing gown, was pacing up and down in the room, while Lestrade was listening to his tale with a look of considerable scepticism on his face. "I'm a newspaper editor for God's sake, and when I find myself right smack in the middle of a murder, I can't seem to put two sentences together that make sense."

Lestrade introduced Sherlock and John, but learning who they were only seemed to rile the editor even more. "Of course, I've heard of you. You're the Boffin and he's the Bachelor." John just put his hand over his eyes in dismay. "Please tell me you aren't the editor of THAT tabloid."

That was the first time the older man smiled. "No, of course not. I'm the editor of a broadsheet quality paper; but I've still heard of you two. Just solve the case will you, and I'll give you a chance to put the record straight."

Sherlock had been ignoring the conversation, instead pacing about the room looking at the modern furniture, the art on the walls. He stopped and asked Harker, "You've lost a small piece of art that went right there." He gestured to a conspicuously empty space on the display shelves beside the fireplace. "And it was a bronze piece by Goldini, wasn't it?"

"Yes, how did you know?"

"That's not the reason I brought you here, Sherlock."

"No, of course not, Lestrade, if you're on the case instead of the Met's A&A squad, then someone got murdered last night- probably has something to do with the theft, however."

"We haven't proven anything yet. The body has already been removed to the morgue."

The editor was still in a state. "I practically fell over it last night, when I came down to investigate a noise. I saw the French door was ajar, went out onto the patio, to find a man with his throat slashed open and a knife lying in the pool of blood. Christ, it was like something out of a bad American cop show."

Lestrade now took over. "He was a tall man, tanned and physically fit. Casually dressed, but no ID on him. There's a phone, but we've not found much on it- one phone call made last night- we're still trying to trace the mobile number it went to, and a photo." Lestrade still had his gloves on, so he took the phone out of the evidence bag and showed it to Sherlock and John. The photo was of a man, shot in bright sunlight, against what looked to be a Mediterranean seascape.

Sherlock smiled. "That's interesting."

"What!" Lestrade realised that Sherlock recognised the man in the photo.

"More like 'who', Lestrade. That's Beppo Goldini, the artist."

Horace Harker looked startled. "Let me see that. I never met the guy, just got the piece from a gallery on the Kings Road." Lestrade showed it to him, just as his airwave radio crackled into life.

"Got some broken bits of metal here, Gov. Think you might want to take a look."

It was seven doors down, in the front garden. Two pieces of twisted metal, a soft green on the outside, but shiny copper from the inside. Sherlock put on latex gloves and handled the piece. A smirk formed in the corner of his mouth. "Interesting, John. The pieces are hollow."

He was on his phone within seconds. "Miss Chambers. I need you to text me with the names and addresses of the other two owners of the Goldini pieces. Yes, you can forget about the one you sold to Horace Harker; I'm there now and it was given the same treatment as yours and the two at the bank. Can you recover those two for me, please, and keep them with yours, for the time being. I will need you to bring them to Baker Street tomorrow morning."

From the confident tone of the call, John realised that Sherlock was well on the way to solving the case. "Care to let me in on the secret, Sherlock?"

"All in good time, John. First, though, I need you to do me a favour. You need to go to the Hoxteth studio and find out who is in the rest of the building. I think you will find that it houses businesses other than artists. Lestrade, you're going to run an Interpol ID search for the body found last night. Odds are he's an assassin, sent to kill Beppo Goldini."

The DI shook his head. "Then he's about 800 miles too far north. According to the Italian authorities, Goldini is in Polistena; that's in Calabria, I'm told. He has a studio there."

Sherlock was smiling at his phone. "As you say, Lestrade. However, if you will meet me tonight at 8pm at this address in Chiswick, I shall happily prove you wrong."

And so he did. The DI and a constable watched from inside the house in Chiswick, and Sherlock and John from the back garden's shed, as a black clad figure broke into the house and emerged only a moment later carrying a small statue. On the pavement stones, he took a chisel out of his pocket and proceeded to gently tap at it. There was a groan of despair and then he pulled a mallet out. Laying the statue on the ground, he proceeded to smash it to pieces.

Sherlock whistled, and the constable sprang into action. Caught in the bright security light that came on, the figure dropped the mallet and sprinted to the garden fence. John was quicker. Caught his legs and hauled him back onto the grass. Lestrade pulled the man's balaclava off and shone a torch onto his face- it was Beppo Goldini.

The DI was amazed. "But, why? Sherlock, I don't get it, why on earth would an artist go around smashing up his own art work? It makes no sense!"

"It makes perfect sense, and if you join us tomorrow morning at Baker Street at ten o'clock in the morning, I will show you why."

The next morning John poured coffee for Lestrade and Miss Chambers. Then to John's surprise, Mycroft came up the stairs carrying a box. He gave his brother a smile, and the box. "As requested, collected from the owner in Bristol."

There on the dining room table were five piles of smashed, twisted and broken metal. Sherlock opened the box and unwrapped a sixth perfect statue. He retreated to the kitchen, "Pour yourself a coffee, Mycroft, shan't be a moment." The doctor didn't go much for modern art, but this was special, and as he sipped his coffee the four of them stood around the table, admired its strange textures, swirls and almost muscular shapes, all softened by a deep patina of green.

Sherlock came out of the kitchen wearing goggles, carrying a large glass bowl and a glass bottle with a pump spray fitting on the top. He placed the figurine in the bowl and pulled on a pair of heavy-duty rubber gloves. "Stand back, this is a weak solution of nitric acid, but it will react. You might want to open the window John; it can be a bit smelly." He started to spray the copper artwork. Within seconds a horrible smelling brown vapour began to steam off the copper, and blue liquid began to accumulate in the bottom of the bowl. Then he grunted, and stopped spraying, pulling off his goggles in triumph. "There it is."

He picked up a pair of tweezers and carefully removed a small piece of dark metal that had been embedded in the statue, hidden under the green.

He held up the sliver in the tweezers, for the others to see. "This is a very interesting item- a tantalum capacitor, built around a new ceramic foil. Very hush, hush. Stolen from the same building of Goldini's London studio. Mycroft, once the acid has been dried off, you can return it to its proper owner."

"Thank you, Sherlock. We have improved the surveillance and security at the design sub-contractor, so it shouldn't happen again."

Miss Chambers was looking really confused. "Mr Holmes, I really don't understand."

"It's basic chemistry. Take one artist who has a studio in the same building as a defence contract design company, add greed and an interested party in the shape of the Camorra – that's what the mafia are called in Calabria by the way- then introduce a catalyst, probably Chinese, who want to lay hands on the latest piece of military aircraft avionics, and you get this case."

"Interrogation will probably get him to confess to the thefts, Lestrade, and to the murder. He was lucky to kill an assassin. I'm sure he'll confess if you threaten to let him go. Whether a Camorra cutthroat or a Chinese agent got to him first would be an interesting wager to make, if I were a betting man. Goldini must have stolen the capacitor, and then realised that he needed a safe place to put it. He carved a niche in one of the six statues he was making, inserted the sliver and then finished with the process of creating the copper carbonate finish- verdigris to you. That hid it well, so he went back to Calabria to negotiate a price with the Camora. Took a while to agree- possible because they held an auction to ensure they got the highest bid."

He smirked. "Mycroft by the look on your face, it must have been higher than what the British could afford to get it back."

The elder Holmes looked down at his umbrella. "I couldn't possibly comment on such wild speculations, brother."

Sherlock continued. "Goldini comes back to recover the chip to discover that he's forgotten which of the six he put it into. He thought it was in one of the two at the Barnicot Bank, but when he burgled them, found he was wrong. So, he started recovering them one by one, trying to find the capacitor. He covered his tracks by making it look like vandalism."

"Basic chemistry, as I said; you can hide all sorts of things under a layer of verdigris. It provides a shield, protecting the metal underneath from corrosion." He looked over at the gleaming red metal figure. "I rather like it better in the pure copper state, but if the owner wants me to put the green back on, I'm sure I could oblige."

Mycroft stood up. "No need, Sherlock. I bought it off the collector, rather than have to explain why we wanted it back. It's yours. Consider it a souvenir, a token of my appreciation for your help."

**Notes for the Chapter:**

> This is a version of AC Doyle's the Six Napoleons. More fun, I hope.


	3. Chapter 3

**Summary for the Chapter:**

> Copper is a transition metal on the periodic table, derived from Latin cuprum, meaning 'from the isle of Cyprus', which is famed for its copper mines. Romans in the 6th through 3rd centuries BC used copper lumps as money. In the US pennies are made from 97.5% zinc, coated with 2.4% copper; in the 1950s it was the other way around- 95% copper, 4% tin and 1% zinc. In the UK, pennies are steel, coated in copper since 1992. This makes them thicker than the old pennies, and magnetic.

Esther walked into Sherlock's bedroom and pulled the chair from the work table under the window. She put it beside the bed and sat down, whilst looking at the tangled mass of sheet and duvet. Presumably, in there somewhere was a ten year old boy attempting to ignore her. She pulled out a well-worn book from her bag and opened it to a place where there were several loose sheets.

There was no sign of life under the bedclothes, no acknowledgement of her presence. Of course, he knew she was there, but if he wanted to pretend she wasn't, then she had to find a way to make him come to her, rather than the other way around.

"Sherlock. What's the chemical symbol for copper and where is it on the periodic table?"

She didn't expect an answer. But, it should start him thinking. She consulted the handwritten grids, and their dates. "It's important whether you know the answer or not. In March, you did. Then in April, you still knew it. But in early May, you'd forgotten it. And you still couldn't remember it in mid-May. So, I have to ask you now- letters and numbers for copper. Any idea?"

There was a slight movement on the bed, then a disembodied voice.

"Cu, 29, atomic weight 63.546. A transitional metal in the D block on the table. Twenty nine isotopes- that's a coincidence, nothing to do with its periodic table number. No allotropes."

She smiled. A few dark curls from a tousled head edged out from under the blankets at the wrong end of the bed- near the footboard rather than the headboard, "Why do you want to know?"

"Because it matters if you've remembered it, or whether you re-learned it since you got back home."

For a moment, nothing. Then the bundle of sheets moved, and the boy sat up.

"WHY? Does it matter?"

No eye contact, he was looking down the far end of the room rather than at her. Following his line of sight, she smiled. He was looking at her, in a way- her reflection in the full length mirror that was on the back of the door she'd used to come into the room. She looked back at him rather than the mirror, so they wouldn't have direct eye contact.

"Do you know why you were forgetting it, when you were in the clinic?"

A shadow seemed to chase across his face. "They wanted me to be stupid. The pills, the mask. They were making me stupid, making me forget things."

"Which is why you starting testing yourself, using the table." She held up the sheets and the book, so he could read the title in the mirror. Even with the letters appearing backwards in the reflection, he recognised it, and turned to her.

"Oh, that's MY book!"

She handed it over to him. "Why's it important?"

In a matter of fact tone, Sherlock just said "Mummy gave it to me; a birthday present. It's all I had to read."

"Why didn't you ask for another book?"

"They just had  _children's_  books; boring. The others on the ward- they just wanted to  _play_  with toys and read  _boring_  books." His distain was clear. "This was the only good book there, so I read it."

 _Now I need to know just how clever he is._  "If you read it over and over again, you must know it by heart. Can you remember what's on page 200? Don't peek."

He was surprised by the question but thought about it for a while. "256 pages, including the index. Metals- definitely. Not Gold, silver or copper; the book does those together first. Then tin and lead. Must be mercury." He opened the book, turned to page 200 and smiled.

_He likes being right. Either eidetic or close to it. It must have been terrifying to find things…missing._

"You're not stupid, but you let them think you were. Why?"

He looked away from the book, but didn't glance at the mirror. His hands were gripping the hard-backed covers tightly.  _This bothers him; it upsets him that others think that of him. So, more socially aware than he might let on._

"Father thinks I'm stupid. He tells me that; I think he told them, too. I don't care what they think."

 _Ouch. It won't hurt if you deny that it does. Protective barriers, indeed._ "Your brother doesn't think you're stupid."

"My brother doesn't think of me much at all."

_Ouch, again. I hope Mycroft isn't out there hearing this._

"He's the one who found you. It took him a long time, because you were very well hidden. He asked me to help find you."

Sherlock looked down at his book. "He's already counting the days until he goes back to university. He's always leaving. First, prep school, then Eton, now Oxford. When he's done with that, he'll get a job and leave again. That's the way he is."

The boy's voice was unemotional, but after he finished, Esther could see that he was now becoming disturbed. "Why does that upset you?"

"Because when he goes, Father will come back, and then there won't be anyone here but him and me. He  _hates_  me."

Esther resisted the temptation to try to argue with the boy or try to tell him that a parent, even a distant one, wouldn't abandon his own son. She had not met Richard Holmes, and only seen him through the eyes of his elder son. And it was possible that Sherlock was right.

Since emotional development and empathy was a key diagnostic of autism, she had to probe.

"What does it mean to you- do you  _hate_ anything or anyone?"

He thought about it a moment, then said in a flat tone. "To hate – abhor, loathe, detest, abominate. It means to feel intense dislike."

"That's what a dictionary says. Do  _you_  hate anything or anyone?"

The boy considered. "Mummy says,... no…she  _said,_ I have to use past tense… that I hate spinach because I can't bear the texture or the taste. I don't like it, and given a chance, I spit it out if someone forces me to eat it."

Esther smiled.  _He's dodging this; he knows exactly what I mean._ "Try again, Sherlock. You know what I am asking."

He frowned. "I don't KNOW what it means, do I? I just know that sometimes I get scared and then my hands start doing things they're not supposed to. I don't like that, so I try to avoid what does that to me, and that makes me even more anxious. Is that 'hate'?"

"Maybe. What makes that happen for you?"

"When I go somewhere new and there are too many people, too many faces I don't know, too much to see, hear, smell- it just scares me. Fight or flight, that's what Mummy called it. Made me try to stay, but that just ends up with me doing something wrong. That's why it happens a lot when Father is near. I get too upset; can't control things."

Unconsciously, the boy was picking at the edge of one of pages of his book, crumpling it between his fingers.

"Why do you think your father hates you?"

"Because he thinks I'm stupid. He thinks I should be sent away. He always said that. And now he thinks I killed Mummy."

Her heart sank. For a vulnerable child to lose one parent was devastating. The idea that he'd been rejected by the surviving one was even worse. But to think that he was being held responsible for the death of the one person with whom he had formed an attachment, well, it was hard to contemplate.

"Why do you think that?"

"Because he told me. We were in the car on the day after Mycroft left. He said Mummy was dead, and that I'd taken the best years of her life away from her, made her sick and she died. Now that she was dead, he would finally do what he'd always wanted to do, which was send me away." It was said in a monotone. No anger, no distress.

"Did you argue with him? Tell him he was wrong?"

Sherlock looked over at her in surprise. "Why would I do that?"

"Because your mother died of cancer, Sherlock, not because of you or anything she did with you."

"It doesn't matter. He hates me, he always has, and now he has even more reason to hate me. When Mycroft leaves again, Father will come back and then send me away to that place again. Only this time, he'll get the doctors to do something that means I forget everything. And not even Mycroft will be able to find me. He's got his own life to live; that's what Father says, and I must not bother him."

"How does that make you feel about Mycroft?"

Now he looked confused. "What do you mean?"

"Do you hate Mycroft?"

"No. He's right to leave. He's perfect and I'm not. Why would he care what happens to me when he isn't here?"

She could hear an undercurrent of anxiety in the tone of voice, and realised she had to act fast if she wasn't going to lose his attention. But before she could react, Sherlock shut the book and stuck it under his pillow. "I don't want to talk anymore. My stomach hurts."

"That's probably because there is nothing in it, Sherlock; you should have eaten Mrs Walters' breakfast. I did and it was delicious. Before I go down to enjoy some of her coffee and pastries, I'm going to leave you with a present." She put three pennies down on his pillow. One of them was brand new, gleaming and shiny. The second one was a very dark brown, the third green. "Tell me the difference."

Sherlock looked at them and his brow furrowed in concentration. "That one's new." He put his head down close to the shiny penny, focusing on it carefully. "No, not just  _new._ Give me the magnifying glass on the table behind you." Bemused, she did as ordered. He examined the shiny penny. "It's in  _mint_  condition; hardly been exposed to air. Where did you get it?" This was delivered in a voice slightly higher pitched with excitement.

"The Royal Mint. Brand new- took it out of the plastic package about fifteen minutes ago."

He was on his elbows now, using the glass to look at the other two on the pillow. "The dull brown one's got a layer of copper oxide.….with a few faint traces of copper sulphide- that's green. Happens when copper is exposed to air; think of it as burning, just really,  _really_  slowly. The brown penny has both in the tarnish layer but it's been in people's hands and pockets, so the green suflide gets knocked off; it's a powder." He moved onto the third penny, the green one. "This penny- it's been in the sea, I think. That means it first formed cuprous chloride, with the sea salt, then cuprous oxide and cupric hydroxide, before turning this colour green, which is malachite- that's CuCO3 CU(OH). That takes a  _long_  time. Given the state it's in, this one is old- not just plated, but ninety five per cent or more copper, so it's old, really old."

She smiled. His attention had shifted away from thinking about his family and his time in the clinic. She set him a challenge. "The corrosion is so bad that I can't read the date. Think you can clean it up enough?"

Almost instantly, his mood brightened. "Of course." He looked at it closely again with the magnifying glass. "Can't read the writing, but it's a King's head, not a Queen, so before 1952. People don't want these to be too clean; hurts the re-sale value if it looks like new. So, I will have to use a dilute acid. Maybe citric-based or vinegar, not sure which to start with."

"Would you like me to bring up one of the books in the library to help you study them more?"

He thought about her offer. "You won't know the right one, so I'd better get it myself."

"You will need to wash and get dressed properly, if you are planning to spend time in the library."

He was already out of the sheets, and she watched the ten year old streak to the bathroom, totally unselfconscious about his own nakedness. She smiled.  _The chemistry works. We can do this._

oOo

"An overnight trip to Cambridge? To stay at your old college? Yeah, I think I can fit that into my diary." If John was surprised at Sherlock's request, he hid it well enough not to arouse his flatmate's suspicions. The chance to get to know more about Sherlock's earlier years was too good to pass up. The man was incredibly reticent about his past, and John's natural curiosity meant he was more than happy to accompany him.

On the train up from Liverpool Street to Cambridge, Sherlock explained. "The Master of my old college called last night, asking for my help on a case. At first, I was inclined to say no, especially when he told me it involved the theft of some papers from his office. More cause to get the police in. But, he made a case that this was not an ordinary theft; it risked exposing not just the college but also the University itself to a significant scandal, and that every attempt had to be made to keep it absolutely quiet."

"How long do you think it will take?"

"Can't say until I know more about the particulars, but he said if the theft wasn't solved by midday tomorrow, then it will become public, so we have a tight schedule. He offered us a night's college accommodation and dinner at High Table tonight. If you can be bothered with that sort of thing, Trinity's wine cellars are famous."

After that explanation, Sherlock lapsed into silence, reading a science journal. John looked out at the English countryside. Once free of London and the suburbs inside the M25, green fields and small villages took over. The train made a brief stop after passing through the light industrial landscape around Peterborough and then at Newark North station, before farmland reasserted its hold. These were the Cambridgeshire Fens- flat agricultural land criss-crossed with canals and drainage ditches.

John had never been to Cambridge, so he was curious when they arrived at the station. Of course, he'd heard about the place, seen pictures, stuff in films and TV, but the station was surprisingly modern and frankly, rather dull. Sherlock just said "Green Street" to the taxi driver, and turned on his phone, ignoring the journey into the centre of the university area.

The cabdriver's request "Is here all right?" was answered by Sherlock's terse "Yes".

They walked the last 150 meters, turning right onto Trinity Lane and then through a brick and stone gate. John stifled a giggle as he wondered whether it had served as a film set for one of the Harry Potter films. Sherlock obviously knew the way, and turned left to a glass fronted reception signed 'Porters Lodge'. A rather stern looking grey-haired small man in uniform came to the window, and asked whether they were tourists or had college business.

"Holmes and Watson; we are here to see the Master."

After consulting a PC screen, the man nodded, and handed through two badges. "You'll need these to access the rooms you've been allocated tonight. In Neville's Court, staircase four; it's a set with two bedrooms for visiting fellows. You swipe the key cards to get access to the staircase. I'll get someone to take you over."

"No need. I know the way." He collected the door keys and turned back to John, a smile on his face.

"Excuse me, gentlemen. The Master is expecting you at 4pm."

"Thank you, Hobbs."

That made the man stop for a second. "Holmes… oh, THAT Holmes. '97-98. Studies suspended. Come back to finish it off then?"

That comment wiped the smile off the brunet's face. Sherlock did not turn around to look at the Porter, but strode out with John trailing behind. When they passed through the arch and into the Great Court, John ground to a halt in amazement. It was MASSIVE, and dominated by an ornate stone carved round structure in the middle. _Why do I recognise this?_

Over his shoulder, Sherlock called out, "You've seen it before, in the movie  _Chariots of Fire_. Come on, John; you can sightsee later."

Just before four o'clock, they came back across the Great Court to the Master's Lodge, an Elizabethan brick building that seemed at odds with the rest of the grey stone buildings on the other sides of the square. They were greeted at the door by a man in college livery, who took them upstairs into a drawing room. "The Master will be with you in just a moment. Please make yourselves comfortable." He poured them a cup of tea from the fine china service on the table between the two sofas. John took in the gold embossed ceiling and the ornamental fireplace, with the royal coat of arms carved into the stone. He recognised it from his army days, but it was subtly different. He was trying to spot the differences, when Sherlock followed the direction of his gaze and said, "Queen Elizabeth. The first one, not the current one. Her father founded the college."

Before John could react, a tall, spare man entered the room, brimming with nervous energy. "Please, don't get up. Holmes, Doctor Watson, I'm Hilton Soames, and I am so grateful to you for coming on such short notice." He sat down on the sofa opposite them, but could not be still, clearly agitated and distressed.

"We have had a very painful incident here, and really without your help, I fear that I have no idea what to do. There is so much at stake, but if you can solve this without getting the police involved then there is a chance we can spare the college and the University a great scandal."

Sherlock gave the man one of his slightly pained smiles. "Then let's not waste any time, Doctor Soames. Tell us what happened."

"Tomorrow is the examination for the John Pople Prize in Quantum Chemistry, to honour his 1998 Nobel Prize. You must have heard of the Pople prize, Sherlock. It was launched here in 2000. It's awarded every third year to the outstanding exam paper result. It's quite a prize- £50,000; one of the most substantial for an undergraduate for the whole university. The answers are adjudicated by a panel from the Chemistry faculty. I invigilate the exam, which is being held here in the Newton Library. "

He stopped for a moment and gave Sherlock a closer look. "Shame it wasn't around in your day. Might have made a difference; kept you interested enough."

Sherlock did not respond. Doctor Soames smiled a little tentatively at John. "I was Sherlock's Director of Studies here for the two years he was with us."

"If, as you say the matter is urgent, then it would be best not to waste any more time, Doctor Soames. Just the main points, please." This was delivered in a typically brusque baritone.

"Yes, well. The exam is being sat by 35 candidates, drawn from the very best students at the whole university. The papers were delivered to my study yesterday. I opened the pack to ensure that the material was printed correctly and counted to make sure that all 35 papers were there. The Prize panel is very particular to ensure that there is no chance of any student getting a prior look at the material, as that is about the only way one could cheat in this exam. So, I locked up the pack in my desk and went off to tea at Trinity Hall. I was sure I locked the door to the room as well. An hour later, when I returned, you can imagine my surprise when I found there was a key in the door, and the room unlocked. The only other key in existence is in Bannister's care- he's my man-servant. He's looked after me in college for the past ten years, and is utterly trustworthy, if a little forgetful these days; he retires at the end of term. Any other time, leaving my office door unlocked would not have mattered, but given the prize, it mattered."

"When I realised what had happened, I called Bannister and asked how his key came to be in the door. He said he had arrived with my usual tea tray at 4pm; he'd forgotten that I was to have tea out of college. As soon as he saw I wasn't there, he remembered my appointment, and left the room. Because of the tray, he didn't take his key with him, thinking he would return later. But he forgot. His attention to detail is not what it used to be."

As if he could no longer contain his agitation, Soames stood up and started to pace in front of the fireplace. "I went in and discovered that someone else had been in the room. The window seat cushion was awry, and the Turkish carpet rucked up. Both had been in order when I left. The curtain which I regularly draw to keep the sun off my desk had been pulled back. Bannister swears he saw nothing out of place when he popped his head in with the tea things. The desk drawer was still locked." Here he reached into his pocket and pulled a key ring out." There is only one key, fortunately. But, then I saw the sheet on the floor beside the side table by the window. It must have slipped down there when I was putting the others away. So, the Pople Prize paper could have been seen by anyone who came into the room when it was unlocked." The dismay on his face was clear.

"Bannister is devastated by the news, just distraught that his error could have led to this. So much so that I've sent him to his rooms; he's not fit for work today. You were shown in by one of the Porter's Lodge staff."

Soames resumed his pacing. "You see my dilemma. It's just…inexcusable. It throws the whole exam into question. I should inform the prize committee immediately, but I have held back for the shame of it. Either you must find the perpetrator, or else the exam will have to be postponed until a new paper can be set. This will have to be explained, and a cloud of scandal will descend on the college, and the University. The Pople Trustees might decide to take away the prize and award it at Carnegie Mellon University in Pittsburgh- that's where Pople actually did his work after graduating from here. There is so much at stake." He wrung his hands.

Sherlock stood, and John followed suit. "I'd like to see your study, if I may, Doctor Soames."

The man nodded and took them across the corridor. Unlocking the door, he started to step in, but Sherlock moved quickly to bar his path. "Please, the fewer people in the room, the more likely I will be able to spot some evidence that will lead us to the perpetrator."

He took a few steps into the room and to the side, then squatted down to look carefully at the carpet. "Did you touch anything after you discovered the problem?"

John and Soames stood in the doorway. The Master answered, "No, apart from checking the desk drawer for the other papers. And I did return the sheet to that drawer. Otherwise, it is as I saw it late yesterday afternoon."

Sherlock walked to the desk and examined its surface, using his pocket magnifier, then went to the window, where he looked out onto the immaculately cut lawn. "Across the Court, in the rooms over there, are there any students sitting the prize exam?"

"Oh, I hadn't thought of that! Yes, there must be. I will consult the list. Can I come in and get to my desk?" Sherlock nodded, then watched the Master unlock the drawer and remove the envelope. He drew the sheet of candidates out and scanned down the sheet.

"Yes- we have five Trinity students taking the exam, three of them are in Great Court rooms; Daulat Ras, she's an Indian student, brilliant mathematician. Then Miles McLaren. Yes- he's related to the Formula One McLarens, a bit of a lazy sod, but still an adequate chemist. And then Gerrard Gilchrist. He's here on an athletics scholarship, a decathalete. His father attended college here. Gilchrist may not make a first class degree, but hopes the prize will make up for it and help his physics career prospects."

John looked a little surprised. "Physics, mathematics- I thought it was a chemistry prize?"

"It is, Doctor Watson, but Pople is known for working at the intersection between chemistry, physics and mathematics. His trustees work hard to do justice to his legacy. He died in 2004. They set the exam question based on his private notes- which is also why it would be  _so_ embarrassing to have to tell them that our security has been compromised."

Sherlock stood thoughtfully at the window, his hands drawn up together under his chin. The Master just watched him, silently as the minutes ticked by.

Then abruptly, Sherlock turned back to the room. "I believe I can make progress on this matter for you."

Soames gave a sigh of relief. "You think one of them did this?" He looked across the quad.

"Perhaps, I need more data. Is it possible that the three of them will be dining in college tonight? Will there be an opportunity to observe them from the High Table?"

Soames beamed. "Of course, in fact, you can clap eyes on all thirty five of the candidates, because they are being entertained to a meal here as part of the process. I can ensure those three sit nearest, and you can even meet them at the drinks reception in the junior common room. The other Prize Panel members will be there, too."

"One last thing, Doctor Soames. I need a see a copy of the exam paper now. It will be a material factor in deducing which is the culprit."

Without a word, the Master reached into the packet of papers, withdrew one and handed it over. As Sherlock scanned down the paper, a smile starting to form on his lips. By the time he reached the bottom of the sheet, he was grinning. "Excellent, excellent question and it will be relatively straight forward to catch this cheat."

That night John was treated to his first ever High Table. Dining in college at his university had been a case of grabbing food from the cafeteria, but as most of his classes had been at one or other teaching hospital, that was most often a hospital cafeteria. Medical students at London University endured a five year course that left little time or energy left for ceremonial functions. His social life had consisted of taking girl friends to see a film, or rugby games with the boys. So, he was somewhat intimidated when he and Sherlock went into the JCR to be greeted by a sea of black gowned smart-suited young people.

If John felt intellectually challenged by the undergraduates, he was positively intimidated by the academics. The Master took them in hand and started making introductions. After ten minutes, John was reeling from trying to keep them all straight.  _Only place I've been where there are more doctors than at a hospital_. For a man who professed to dislike crowds of people he didn't know, Sherlock seemed oddly at home. That is, until one of the dons to whom Soames introduced him started to smile, rather maliciously. "You don't remember me, do you, Holmes? I was in your inorganic lab seminar group. You always thought you were too clever by half to do things the way the experiments were set out. Still, I suppose a little smattering of chemistry makes you sound the part in your trade. No wonder the tabloids love to call you Boffin." The sneer was evident on the chubby man's face.

For a moment, Sherlock just went still. John could see him deciding whether the effort was worth it. John murmured quietly, "he's a prat, just ignore him."

The brunet started to turn away. But the don wasn't finished. "Probably can't remember me because you were so wasted on cocaine that it was amazing that you could even find the lab."

That was enough. The detective turned to his tormentor. "Oh, I remember you, Charles Quinton. Who could forget the final year student forced to repeat that class because your ineptitude meant you only managed to pass the practical on the third and final resit attempt? Nice to see that your father's generous contribution to the Biomedical Research Centre was conditional on finding you a research fellowship. After all, we both know that your post would never have been awarded on merit. Your family has always been so  _supportive_  of your career, haven't they?"

Before the red-faced academic could respond, John steered Sherlock away. At the drinks table, he looked at his friend. "The guy's an idiot, don't waste the energy."

Sherlock surveyed the people in the room. "Most of them  _are_  idiots, John. That is the reason why I left." But John noticed how quiet his friend was for the rest of the evening. Trinity College's dining hall was an astounding room, and John's eyes kept wandering up to the hammer-beamed roof. The enormous oil painting behind the high table was of Henry the Eighth, and beneath his royal gaze, the finest chemistry undergraduates at Cambridge were fed a three course meal. John enjoyed his roast duck breast in a redcurrant and burgundy sauce. He noticed that Sherlock ate very little, and put his hand across the crystal wine glass each time the waiter appeared at his elbow. The doctor was kept entertained by a talkative and attractive red-haired woman in her thirties on his left, a research fellow in medical bioengineering. She was fascinated to hear his stories about battlefield surgery techniques in Afghanistan. His attempts to involve Sherlock in the discussion were politely but firmly deflected. Apart from the occasional word with the Master, the brunet spent his time observing the students.

The long table at which they were seated was made for such scrutiny. The academics and guests sat all in a row on one side, facing out to three long perpendicular rows of student diners. It was actually a 'high' table, up on a dais about fifteen inches above the rest of the hall level, which gave them a perfect view of the students. Sherlock was focussing most of his attention on the three that Soames pointed out to him; Daulat, Miles and Gerrard.

When the main course plates were taken away, Sherlock excused himself. "I will see you back at the rooms, John. Take your time. Port and coffee in the SCR will follow the pudding course. I will be investigating the three suspects' rooms, together with Hobbs, the Head Porter."

When John got back to the Neville court rooms, it was late. The wine, the port, the excellent food and the red-head's laughter just pushed him into a haze of contentment. He found Sherlock sitting at a table in the shared living room between the two single bedrooms. He had a pad and pencil out and was flipping a penny coin.

"Bored? Sorry, things just…went on a bit."

"They always do at Cambridge, which is why I was glad to have an excuse to leave early. And, I'm not bored."

John looked at a second coin which now lay flat on the pad, brown and duller than the one in Sherlock's fingers. The brown one on the table was slightly thinner in width. "An old coin?"

"Yes. I'll explain tomorrow."

"Solved it then?"

"Good night, John. Pleasant dreams."

Whether it was the wine or the food, John managed eight hours of blissful sleep. He was woken by the sound of Sherlock in the shared living room. "Come on, John. I've been up an hour and we need to put Soames out of his misery. He will be in a dreadful fidget until we can lay his mind at rest. Can you do without breakfast?"

Fifteen minutes later, they made their way to the Master's Lodge, where they found Soames anxiously pacing. His face was lined with worry and it was clear he had not slept at all. Unshaven and clothes thrown on, he seemed on the edge of exhaustion. "Ah, Holmes. Have you come to the rescue? Or do I have to call the Panel to postpone the exam?"

Sherlock smiled. "Let it proceed, by all means."

"But, is there a cheat? Who is the rascal?"

"Summon your servant, Bannister. I must start with him before we confront the guilty party."

"He's back on duty this morning, so I can call him in now."

When the elderly and slightly stooped man came into the study, he took in the presence of Holmes and Watson, and his face fell. The Master directed him to take a chair, and then leaned back in his chair behind his desk with a set frown.

Sherlock looked down at the servant. "Now, Bannister. Will you please tell us the truth of yesterday's incident?"

The man turned white, to the roots of his hair. "I have told the Master everything."

"Nothing to add then?" It was mildly said, but with more than a hint of menace in the baritone. For a moment, all John could think of was Mycroft.  _He's channelling his brother to put the fear of God into this poor sod._

The man was clearly shaken, but he stood fast. "No, sir."

"Ah, that's a pity, Bannister. I thought to give you a chance to put it right. You've served the college well and it seems sad to go out on such a sour note. Still, remain where you are, please. Doctor Soames, can I ask you to go up to the room of young Gilchrist, and escort him down here now?"

The Master left, and Sherlock paced. The servant's eyes followed his tall figure back and forth, his obvious distress rising with every step. The doctor began to worry that he might have heart trouble.

When Soames returned, the student followed him into the room. He was athletic in build with a fine spring in his step, until his blue eyes caught sight of the other occupants of the study. "Oh, Bannister. Don't tell me. How did they know?"

"I've not betrayed you, young master. I haven't said a word. They can't prove a thing."

Sherlock frowned and reached into his pocket. "Then perhaps you can explain this, which I found on the desk in your rooms." He pulled a metal bar that was about three inches long from his pocket. He showed it to the Master. Soames looked at it for a moment, and then he nodded. "Yes- a magnetic stirrer. That would do."

Gilchrist just whispered, " _damn."_

The old servant turned to Soames now, and in a pleading voice, began to confess. "It's all my fault, sir. I brought the tea tray in as I said, and that's when I spotted the paper. I told the boy to come down and use my key to let himself in and take a look. He  _needs_  to win this prize, sir, he really does. His father died at the start of last term and the house has been repossessed. The College Bursar says he's not eligible for financial help, because of his family wealth. But it's all tied up in contested property deals; will take years for probate to come through. He's not got a stitch of ready money to his name, and I can't afford his fees anymore. It was hard enough this term, but next, when I am on a pension, I just can't do it."

The effect of this speech on the young man was devastating. His eyes filled and he let a strangled gasp out. "Stop it, Bannister; this won't do. You can't risk your position and your pension." He turned to Sherlock. "It's my fault. All my fault. He told me of the opportunity and like a fool, I took it. Came in and found the sheet, took it over to the window to take a photo with my phone, needed the extra light. If you ask me why I was tempted to cheat, well, I have to be honest about that. I'm desperate, in debt and no hope of paying my fees. Without the prize, I will have to quit and take whatever job I can get. Just don't make him suffer; he's been too kind to me."

Sherlock turned away from the bookcase, which he had been surveying during the emotional outbursts of the old man and the student.

"Bannister, tell us how you know the Gilchrist family. A former employer perhaps?" The old man just nodded, his face now wet with tears. "And some misguided sense of loyalty led you to think that cheating was the best way to help express that loyalty." Another nod.

"Doctor Soames, you have your confession. The prize exam can proceed, and the reputation of the college and the Pople Prize is intact. Gilchrist, based on the set of calculations I found on the pad under the magnet, you do have the makings of a competent chemist, if not a very bright one. Perhaps a suspension of studies, until such time as you have earned the fees you need through hard work at a lab bench somewhere in the Cambridge Science Park- perhaps that is a fitting enough punishment."

Soames nodded his agreement. "Bannister, go home. We will talk about moving your retirement date closer; it was only a month away in any case. Gilchrist, take him home and then return to college long enough to clear your room. I will process the paperwork for the suspension."

When the two unfortunates left, Soames turned to Sherlock. "Thank you, from the bottom of my heart. A formal rustication would require the circumstances to come out in public, and that would be harmful to all concerned. This is the best solution, and one I could not have foreseen from the depths of my despair yesterday. You have saved the day, Holmes."

"It was nothing. Really rather straightforward, as cases go." He made to leave, and John stood.

"Wait…" The Master came around his desk and drew up to the tall brunet. "I've been meaning to say this for, well, nearly sixteen years. I am sorry we couldn't keep you interested. I was never one of your nay-sayers, although there were some on the College council who wanted you to be sent down for good. It was kind of you to be willing to help us, when the College did not serve you as well as it might have. Thank you."

He offered his hand. Sherlock looked down at the hand for a moment, and then shook it.

As they left the room, Soames said one more thing. "You've solved it, haven't you? You've recalculated the Bernoulli formula to take into account the magnetic force?" Sherlock just smirked.

On the train home, Sherlock buried his nose in the journal article again. John waited until they were out in the countryside again. "Okay, now that there is no one within ear shot who is going to laugh at my ignorance, I have to know. What was all that about? How does a magnet found in a student's room make him guilty?"

The detective gave a wry, small smile. "The Pople prize exam question was set around the physics of flipping a coin. It's a long standing tradition- vast numbers of academic papers have been written on the subject. It may sound trivial, but actually it is a microcosm of chemistry, physics and mathematics in a single understandable activity. The question consisted of two different data sets, a table of probabilities relating to the pre-decimal pence, the second to the current penny. The first coin is between 95.5 and 97% copper, the latter is less than 5% copper plating around a steel coin that is slightly thicker to ensure the weight is the same as the pre-1992 pennies in circulation."

"So that's what you were doing with the coins last night, testing a theory?

"Yes. The second table on the exam paper shows a deviation in the probabilities from what one would expect, even with the metallic difference and the change in thickness. The answer is that who or what was flipping the coin was cheating, by using a magnet to influence the odds. From the data it was possible to calculate the nature of the magnet effect- weak- and to deduce its character. The prize will be won today by the student who is best able to recalculate the Bernoulli formula to take that additional factor into account. Makes me wish that John Pople had taught here instead of going to the USA. It's quite clever, actually." He turned back to his journal article and resumed reading.

John sat back in his seat and smiled at the Cambridgeshire countryside _. It takes one to know one._

**Notes for the Chapter:**

> This is another acknowledgement of Conan Doyle's The Three Students- updated and with a twist of chemistry added to the mix. Occasionally, lines of dialogue from the original have been used- an author's conceit. And the Pople prize is real, too. Sherlock would have liked his approach to chemistry had he been at Trinity during the man's tenure there.


End file.
